1. Technical Field
The present invention relates to a method of manufacturing an electronic device using an anode bonding device.
2. Related Art
Traditionally, as an electronic device having a functional element for detecting a physical amount using, for example, microelectromechanical systems (MEMS), an acceleration sensor, a gyro sensor, or the like that has a functional element on a package substrate (substrate) such as a semiconductor substrate or a glass substrate has been proposed.
For example, JP-A-2013-164285 discloses an electronic device having a lid body bonded on the side of a first surface of a substrate (corresponding to the aforementioned package substrate) and a functional element (sensor element) stored in a cavity surrounded by the substrate and the lid body. As the bonding of the functional element to the substrate and the bonding of the lid body to the substrate, an anode bonding method that is performed using an anode bonding device is applied to the electronic device. Specifically, in a process of manufacturing the electronic device, the anode bonding is performed multiple times or the first anode bonding is performed to bond the functional element to the substrate and the second anode bonding is performed to bond to the lid body to the substrate.
As described in the aforementioned JP-A-2013-164285, however, in the case where the anode bonding is performed on the same substrate two times to bond the functional element to the substrate and bond the lid body to the substrate, alkali metal ions of the substrate are used (move) upon the first anode bonding, and a portion of the substrate becomes deficient in alkali metal ions essential for the second anode bonding and forms a so-called depleted layer. Thus, the lid body is not sufficiently bonded to the substrate by the second anode bonding. As a result, the strength of the bonding of the lid body to the substrate may be reduced, and the airtightness of the lid body and the substrate may be reduced.